class Lookup_Possible(o.Obj):
a, b = keys(2)
class D(C):
c, d = keys(2)
class X1(X):
c = keys(1)
class X2(X1):
d, e = keys(2)
class X(o.Obj):
a, b = keys(2)
n1 = class_attr(1)
n2 = attr(10)
class C(A):
c, d = keys(2)
class B(o.Obj):
a, b = keys(2)
class A(o.Obj):
a, b = keys(2)
class B(A):
c, d = keys(2)